The present invention relates to an airfoil for a nozzle stage of a gas turbine and particularly relates to an airfoil for the second stage nozzle of a gas turbine.
Many specific requirements must be met for each stage of the hot gas path section of a gas turbine in order to meet design goals, including overall improved efficiency and loading. Particularly, the second stage of the turbine section must meet efficiency, heat load, life, throat area and vectoring requirements to meet that goal.
In accordance with a preferred embodiment of the present invention, there is provided an airfoil shape for a nozzle stage of a gas turbine, preferably the second stage nozzle, that enhances the performance of the gas turbine. The airfoil shape hereof improves the interaction between various stages in the turbine, affords improved aerodynamic efficiency through the second stage and improves the second stage blade loading. Thus, the profile of each second stage nozzle airfoil which in part defines the hot gas path annulus about the nozzle stage meets the requirements for improved stage efficiency, as well as parts life and manufacturability.
In a preferred embodiment according to the present invention, there is provided a turbine nozzle including an airfoil having an airfoil shape, the airfoil having a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in Table I wherein the Z values are non-dimensional values from 0 to 1 convertible to Z distances in inches by multiplying the Z values of Table I by a height of the airfoil in inches, and wherein the X and Y values are distances in inches which, when connected by smooth continuing arcs, define airfoil profile sections at each distance Z, the profile sections at the Z distances being joined smoothly with one another to form a complete airfoil shape.
In a further preferred embodiment according to the present invention, there is provided a turbine nozzle including an airfoil having an uncoated nominal airfoil profile substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in Table I wherein the Z values are non-dimensional values from 0 to 1 convertible to Z distances in inches by multiplying the Z values of Table I by a height of the airfoil in inches, and wherein the X and Y values are distances in inches which, when connected by smooth continuing arcs, define airfoil profile sections at each distance Z, the profile sections at the Z distances being joined smoothly with one another to form a complete airfoil shape, the X, Y and Z distances being scalable as a function of the same constant or number to provide a scaled-up or scaled-down airfoil.
In a further preferred embodiment according to the present invention, there is provided a turbine comprising a turbine stage having a plurality of nozzles, each of the nozzles including an airfoil having an airfoil shape, the airfoil having a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in Table I wherein the Z values are non-dimensional values from 0 to 1 convertible to Z distances in inches by multiplying the Z values of Table I by a height of the airfoil in inches, and wherein X and Y values are distances in inches which, when connected by smooth continuing arcs, define airfoil profile sections at each distance Z, the profile sections at the Z distances being joined smoothly with one another to form a complete airfoil shape.